The present invention relates to a power distribution system for modular wall panels and particularly to outlet assemblies used in such systems. More particularly, the present invention relates to outlet assemblies for multi-wire, multi-circuit power distribution systems, having three conductors therein (one line conductor, one neutral conductor, and one ground conductor), where at least one of the line, neutral, and ground conductors within the receptacle can be selectively connected to one of the respective line, neutral, or ground wires of the power distribution system.
An office environment, as well as other work locations, often has several types of electrical and electronic equipment, such as computers, terminals, printers, photocopiers, fax machines, communication equipment, answering machines, heaters, air conditioners, etc. Each of these devices must be "plugged-in" to a circuit of a power distribution system. With multiple electronic equipment, multiple power, neutral, and ground lines are often needed to prevent overloading a single power line with too much current. Similarly, when multiple electronic devices share a common neutral, noise and/or current overload can occur because of lack of current cancellation due to phase shifting caused by inductive loads. "Clean" circuits having isolated grounds for powering of sensitive electronic equipment such as computers are also often needed because this equipment should not be connected in the same circuit where it can be exposed to current spikes or impulses caused by other electric equipment such as air conditioners and heaters.
The modern office environment often consists of a large open area or floor space that is divided into separate and distinct work areas via modular wall panel systems. These modular wall panels can be moved about with relative ease to change an entire office floor plan. This makes it difficult to set up electrical power distribution systems having the plurality of circuits often necessary for the reasons discussed above.
One solution to this problem has been achieved through the use of a plurality of connected, electrically prewired, modular wall panels that have power distribution components installed therein (often called wiring harnesses) that contain a plurality of power, neutral, and ground lines. Examples may include ten-wire systems that can contain such combinations as six power lines, two neutral lines, and two ground lines (one of which may be isolated) which define six different circuits, or four power lines, four neutral lines, and two ground lines (one of which may be isolated) which define four different circuits. A power or circuit tap, can be removably connected to a power distribution system within a modular wall panel to allow point of use connection. An example of a typical power or circuit tap would be the use of a plug-in outlet assembly that may be configured so as to draw power from one of a plurality of circuits in the power distribution system when a standard two-or three-prong electrical cord for an electrical device is inserted therein.
U.S. Pat. No. 4,367,370 to Wilson et al. shows a plug-in outlet receptacle for a five-wire power distribution system having three power lines, one neutral line, and one ground line, thus providing three separate circuits. The receptacle of Wilson et al. includes a switch that connects the receptacle to one of the three power lines via a sliding contact thereby selectively connecting the receptacle to one of the three circuits.
A disadvantage to the use of sliding contacts is that they add resistance, which becomes particularly problematic in environments where high amounts of current are needed. Also, sliding contacts may fail or gap, thus not providing electrical continuity. Finally, electrical sliding contacts add to the expense of constructing the outlet receptacle.
U.S. Pat. No. 4,775,328 to McCarthy discloses a plurality of ports that receive a plurality of plug-in outlet receptacle modules for a seven wire power distribution system having three power lines, two neutral lines, and two ground lines, to provide three separate circuits. Each of the ports has seven terminals that correspond to the seven lines of the power distribution system. In addition, each of the plug-in outlet receptacle modules has a differently configured set of three prongs that engage three of the seven terminals in a port to connect the receptacle to one of the three circuits. A disadvantage of this design is that a plurality of differently configured prongs must be formed for each outlet receptacle. This adds to the expense of the outlet receptacle. Another disadvantage is that a separate supply of outlet receptacles must be kept and located each time an outlet is to be connected to a different circuit. This requires separate stocking of these parts and is an inconvenience to the user.
U.S. Pat. No. 5,131,860 to Bogiel discloses a single plug-in outlet receptacle for a multi-circuit power distribution system. The plug-in outlet receptacle has three blade portions on one side thereof for interconnection with one of a plurality of circuit control modules that connect therewith. Each of the circuit control modules connects with three of the lines (one power, one neutral, and one ground) of the power distribution system to tap into one of its circuits. Each of the circuit control modules has three separately shaped blade portions (one for power, one for neutral, and one for ground). In addition, there are a plurality of circuit contacts mounted in each receptacle assembly that allow connection between three of the lines of the power distribution system and the circuit control module. Bogiel suffers from the same disadvantages as McCarthy. In addition, Bogiel has a plurality of circuit contacts further adding to both the cost and complexity of the design.
U.S. Pat. No. 5,096,431 to Byrne shows an outlet plug-in receptacle that has three internal terminals (one power, one neutral, and one ground) that can each be moved via slidable levers to selected positions for connection with three of a plurality of terminals in a junction block of a power distribution system. The terminals of the junction block are connected to the power, neutral, and ground wires of the power distribution system. This allows the receptacle to be selectably connected to any one of the plurality of circuits in the power distribution system. The three internal terminals of Byrne's receptacle are moved by physically bending the center and end portions thereof.
Byrne suffers from the disadvantage that the sliding assembly may fail. In addition, the sliding assembly adds to the cost of the outlet receptacle. Finally, Byrne's terminals are likely made from an expensive metal alloy because of the need for them to be both flexible and resilient. This too adds to the expense of the outlet receptacle.
Applicant makes no representation by this discussion, nor should any such representation be inferred, that an exhaustive search of all relevant prior art has been conducted, or that no more pertinent prior art exists.
An output plug-in receptacle that solves some or all of the above problems of added resistance, mechanical failure, high cost, required supply stocking, and design complexity would be a welcome improvement. Any new design improvement, however, should be easy to use and offer compatibility with existing systems.
Accordingly, a receptacle assembly is provided which has a body portion having at least one outlet formed therein for receiving an electrical plug. The outlet has a line terminal, a neutral terminal and a ground terminal. At least one input plug is formed in the body. The input plug has a plurality of openings therein. Conductors extending from the outlet terminals to the input plug are also provided. At least one of the conductors terminates in a plurality of terminals that are positioned adjacent a respective plurality of openings of the input plug. Finally, the receptacle assembly includes circuit selector means connected to one of the plurality of terminals adjacent the openings of the input plug. The circuit selector means selectively extends one of the terminals of the conductors into one of the plurality of openings of the input plug. In one embodiment of the present invention, each of the conductors terminates in a plurality of terminals positioned adjacent a respective plurality of openings formed in the input plug. In yet another embodiment of the present invention, the receptacle assembly has two input plugs formed on opposite ends of the body. The conductors extend from the outlet terminals of each of the input plugs such that at least one of the conductors terminates in a plurality of terminals adjacent a respective plurality of openings of at least one of the input plugs. In yet a further embodiment of the present invention each of the conductors terminates in two terminals adjacent two of the openings of the input plug.
The plurality of terminals on the end of the conductors may comprise male terminals. The circuit selector means may comprise a clip having a female terminal on a first end thereof adapted to matingly engage male terminals of the conductors. The first end of the circuit selector means may have anchoring means thereon for securely engaging the male terminals of the conductors. The anchoring means may comprise dimples formed in the first end. The first end may also be substantially U-shaped in cross-section.
The clip may also have a female terminal on a second end thereof adapted to matingly receive a male terminal of an input circuit. The female terminals of the first and second ends of the clip may be substantially orthogonally oriented relative to one another. The second end of the clip may comprise at least one pair of laterally opposed, biased fingers that are sprung toward one another to form a gap that slidingly and conductively receives therein the male terminal of the input circuit. The ends of these fingers may outwardly curve opposite one another and opposite the direction of the bias of the fingers.
The body of the receptacle assembly may have retaining means against which a portion of the first end of the clip may abut. This retaining means prevents the clip from being removed from a male terminal of a conductor on which the clip is matingly engaged when the second end of the clip matingly receives the male terminal of the input circuit. The retaining means may be a rib which may be formed on the body.
In this embodiment, the conductors may be made from either brass or copper and the circuit selector means may be made from high performance copper alloy.
Another embodiment of the receptacle assembly of the present invention includes at least one outlet formed for receiving an electrical plug. Input means for receiving a second electrical plug is provided with conductors connected to and extending from said outlet to said input means. The conductors terminate in a terminal adjacent the input means. Circuit selector means attached to said terminal for connecting said conductors to said input means is provided. The circuit selector means has a female terminal on a first end thereof adapted to matingly receive a male terminal of an input circuit. The input means may consist of a plurality of connection points in which case the conductors would terminate in a plurality of terminals positioned adjacent a respective plurality of the connection points. In such an embodiment the circuit selector means would be attached to one of the terminals.
The terminal of the conductors may comprise a male terminal in which case a second end of the circuit selector means would have a female terminal thereon adapted to matingly engage the male terminal of the conductors. The second end may have anchoring means thereon for securely engaging the male terminal of the conductors. The anchoring means may comprise dimples formed in a second end. The female terminals of the clip of this embodiment may be substantially orthogonally oriented relative to one another.
The female terminal on the first end may comprise at least one pair of laterally opposed biased fingers that are sprung toward one another to form a gap that slidingly and conductively receives therein the male terminal of the input circuit. The ends of the fingers may outwardly curve opposite one another and opposite the direction of the bias of the fingers.
In this embodiment, the conductors may be made from either brass or copper and the circuit selector means may be made from high performance copper alloy.
The receptacle assembly of the present invention may be configured for ten wire systems such as a "6-2-2 system" (a power distribution system having six lines, two neutrals, and two grounds) or a "4-4-2 system" (a power distribution system having four lines, four neutrals, and two grounds). An embodiment of the present invention for a "6-2-2 system" has a body with at least one outlet formed therein for receiving an electrical plug. At least one input plug is formed on the body. The input plug has six line openings, two neutral openings, and two ground openings. A line conductor is connected to and extends from the outlet to said input plug. The line conductor terminates in a plurality of terminals positioned adjacent a respective plurality of line openings. A neutral conductor is connected to and extends from the outlet to the input plug. The neutral conductor terminates in two terminals positioned adjacent the two neutral openings. A ground conductor is connected to and extends from the outlet to the input plug. The ground conductor terminates in two terminals positioned adjacent the two ground openings. Circuit selector means is connected to one of the plurality of terminals adjacent the line openings and connected to one of each of the two terminals adjacent both the neutral and ground openings. Circuit selector means selectively extends the line neutral and ground conductors into a selected one of the line, neutral, and ground openings. In one embodiment, three differently shaped line conductors are provided, each of which terminates in two terminals positioned adjacent two of the six line openings. In another embodiment, the receptacle assembly may include two input plugs formed on opposite ends of the body. In this embodiment, the line, neutral, and ground conductors are connected to and extend from the outlet to each of the input plugs, the line, neutral, and ground conductors each terminating in two terminals adjacent respective line, neutral, and ground openings of at least one of the input plugs.
The terminals of the line, neutral, and ground conductors may comprise male terminals. The circuit selector means may comprise clips having female terminals on the first ends thereof adapted to matingly engage the male terminals of the line, neutral, and ground conductors. The first ends of the clips may have anchoring means thereon for securely engaging the male terminals of the line, neutral, and ground conductors. The anchoring means may comprise dimples formed on the first ends of the clips. In addition, the first ends of the clips may be substantially U-shaped in cross-section.
The clips may have female terminals on second ends thereof adapted to matingly receive male terminals of an input circuit. In this embodiment, the female terminals on the first and second ends of each of the clips may be substantially orthogonally oriented relative to one another. The second ends of each of the clips may comprise at least one pair of laterally opposed, biased fingers that are sprung towards one another to form a gap that slidingly and conductively receives therein the male terminals of the input circuit. The ends of the fingers may outwardly curve opposite one another and opposite the direction of bias of the fingers.
An embodiment of the present invention for a "4-4-2 system" has a body with at least one outlet formed therein for receiving an electrical plug. At least one input plug is formed on the body. The input plug has four line openings, four neutral openings, and two ground openings. A line conductor is connected to and extends from the outlet to the input plug. The line conductor terminates in a plurality of terminals positioned adjacent a respective plurality of line openings. A neutral conductor is connected to and extends from the outlet to the input plug. The neutral conductor terminates in a plurality of terminals positioned adjacent a respective plurality of neutral openings. A ground conductor is connected to and extends from the outlet to the input plug. The ground conductor terminates in two terminals positioned adjacent two ground openings. Circuit selector means is connected to one of the plurality of terminals adjacent the line openings, one of the plurality of terminals adjacent the neutral openings, and one of the two terminals adjacent the ground openings. Circuit selector means selectively extends the line, neutral, and ground conductors into a selected one of the line, neutral, and ground openings. In one embodiment, there are two differently shaped line and neutral conductors each of which terminates in two terminals positioned adjacent two of the four respective line and neutral openings.
As with the "6-2-2 system", another embodiment of the receptacle assembly for the "4-4-2 system" may have two input plugs formed on opposite ends of the body. In this embodiment the line, neutral, and ground conductors are connected to and extend from the outlet to each of the input plugs, the line, neutral, and ground conductors each terminating in two terminals adjacent respective line, neutral, and ground openings of at least one of the input plugs.
The remaining characteristics of the "4-4-2 system", such as the shape of the terminals on the line, neutral, and ground conductors, the characteristics of the circuit selector means, etc. are the same as those discussed above with reference to the "6-2-2 system."
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.